The present invention relates to photochromic 2H-naphtho[1,2-b]pyrans as well as to their use in synthetic resins of all types, particularly for ophthalmic purposes. In particular, the present invention relates to photochromic naphthopyran compounds, for which a further ring system is bonded to the f side of the naphthopyran.
Different classes of dyes are known which, when irradiated with light of particular wavelengths, particularly sunlight, change their color reversibly. This is due to the fact that, because energy is supplied in the form of light, these dye molecules change over into a stimulated colored state, which they leave once again when the supply of energy is interrupted in order to return to their colorless or at least hardly colored normal state. These photochromic dyes include, for example, the naphthopyrans, which have already been described with different substituents in the state of the art.
Pyrans, especially naphthopyrans and larger ring systems derived from these, are photochromic compounds, which until now have been the object of intensive investigations. Although the first patent was filed already in 1966 (U.S. Pat. No. 3,567,605), compounds, which are suitable for use in eyeglass lenses, were developed only in the 1990s.
A suitable class of pyran compounds is, for example, the 2,2-diaryl-2H-naphtho[1,2-b]pyrans. 2H-Naphtho[1,2-b]pyrans generally are orange to red photochromic compounds, which are decolorized very slowly after they have become darker, such as the Comparison Examples 4 and 5 and the Comparison Example A in U.S. Pat. No. 5,066,818.
Attempts were made to achieve improvements here by substituting the carbon atoms in the 5 and 6 positions of the naphthalene part in the naphthopyran. Compounds of this type are described, for instance, in U.S. Pat. Nos. 5,458,814, 5,573,712, 5,650,098, 5,656,206, 5,658,500 and 5,658,501 and in WO 98/04937. Since there was a need for further improvement, 2H-naphtho[1,2-b]pyran systems were described for the first time in U.S. Pat. No. 5,651,923. At the f side of the naphthopyran, that is, at the naphthalene part, these compounds have condensed benzothieno, benzofurano or indolo system, the benzothieno, benzofurano and indolo systems being bound to the naphthalene via the heterocyclic portion. It is disadvantage of the three naphthofuro[2xe2x80x2,3xe2x80x2:3,4]- and naphthofuro[3xe2x80x2,2xe2x80x2:3,4]-naphtho[1,2-b]pyrans of Examples 4, 5 and 6 in U.S. Pat. No. 5,651,923, that these decolorize very slowly and/or have a very slight photochromic efficiency (xcex94OD). Indolonaphthopyrans also decolorize similarly slowly. In the WO 99/20619, pentahydrophenanthro[9,10-b]pyrans and tetrahydrocyclopenta[c]naphtho[1,2-b]pyrans are described, which also have the disadvantage that their decolorizing rate is slow and therefore unsatisfactory for practical use in sunglasses.
In addition, an expensive and long synthesis route is required for the systems described. Furthermore, due to the possibility of conjugating with a further aromatic ring (system), a bathochromic shift relative to the basic absorption of the naphthopyran system may be observed, which frequently is undesirable. This applies likewise for the compounds in U.S. Pat. No. 5,645,767, which relate exclusively to indeno[2,1-f]naphtho[1,2-b]pyrans. Further continuations may be found in U.S. Pat. Nos. 5,698,141 and 5,723,072, which additionally have condensed unsubstituted, monosubstituted or disubstituted heterocyclic systems.
The known compounds are however associated with disadvantages, which affect the wearing comfort of the eyeglasses when these photochromic dyes are used in sunglass lenses. The known dyes have an inadequate long-wave absorption in the excited as well as in the not-excited state. This leads to problems even when these compounds are combined with other photochromic dyes. The temperature sensitivity with respect to the darkening is too high. At the same time, the decolorization frequently is too slow. In addition, the dyes described have an inadequate service life and, with that, in insufficient durability in sunglass lenses. The latter becomes noticeable in a rapidly abating efficiency and/or in severe yellowing. Moreover, the synthesis of the compounds, described in the state of the art, usually is expensive and lengthy and generally does not permit further optically interesting properties, such as a nonlinearity, to be incorporated into the respective structures.
Accordingly, it is an object of the present invention to make available new photochromic compounds, which have improved properties in comparison to the structures described in the state of the art. The photochromic compounds are to be distinguished particularly owing to the fact that they have faster kinetics in the light-stimulated state, than do comparable compounds from the state of the art, and exhibit a better behavior in the service life test.
This objective is accomplished by the objects, characterized in the claims. In particular, photochromic 2H-naphtho-[1,2-b]pyrans of the general formula (I) are made available 
wherein
X represents a ring element with 2 to 4 saturated and/or unsaturated carbon atoms, of which not more than one can be replaced by a hetero atom, selected from the group comprising O, S and NR4, R4being a linear or branched C1 to C6 alkyl group, a substituted or unsubstituted C5 to C7 cycloalkyl group, a substituted or unsubstituted phenyl group or a substituted or unsubstituted benzyl group;
R1 is a substituent, selected from group A, comprising a C1 to C6 alkyl group, a C1 to C6 alkoxy group, a C3 to C7 cycloalkyl group, which may have one or more hetero atoms, a phenyl group, a hydroxy group, bromine, chlorine and fluorine, n being 0, 1 or 2;
R2, R3 independently of one another are groups, selected from group G, comprising hydrogen, hydroxy, a C1 to C6 alklyl group, a C1 to C6 alkoxy group, a C3 to C7 cycloalkyl group, an unsubstituted, monosubstituted and disubstituted phenyl group and an unsubstituted, monosubstituted and disubstituted naphthyl group and the aromatic groups, selected from group C, comprising benzene, naphthalene, phenanthrene, pyridine, quinoline, furan, thiophene, pyrrol, benzofuran, benzothiophene, indol and carbazol, the substituent or substituents of the aforementioned aromatic groups being selected from group A;
or R2 and R3 together, with inclusion of the spiro carbon atom, form a 5-membered to 11-membered ring, to which one or several aromatic or heteroaromatic ring systems may be annellated, the aromatic or heteroaromatic ring system or systems being one of the aforementioned group C;
or R2 and R3 together represent an oxygen atom with formation of a carbonyl group;
with the proviso that, when X is xe2x80x94(CH2)2xe2x80x94 or xe2x80x94(CH2)3xe2x80x94 and R2 and R3 are not at the same time hydrogen;
B, Bxe2x80x2 are selected independently of one another from the following groups a), b) or c), wherein
a) are mono-, di- and trisubstituted aryl groups, the aryl group being phenyl or naphthyl;
b) are unsubstituted, mono- and disubstituted heteroaryl groups, the heteroaryl group being pyridyl, furanyl, benzofuran-2-yl, benzofuran-3-yl, thienyl, benzothien-2-yl or benzothien-3-yl; the substituents of the aryl groups or the heteroaryl groups in a) and b) being selected from a group comprising hydroxy, amino, mono-(C1 to C6)-alkylamino, di-(C1 to C6)-alkylamino, mono- and diphenylamino, unsubstituted, monosubstituted or disubstituted at the aromatic ring, piperidinyl, morpholinyl, carbazolyl, unsubstituted, monosubstituted and disubstituted pyrryl, C1 to C6 alkyl, C1 to C6 alkoxy, bromine, chlorine and fluorine, wherein the aforementioned aromatic and heteroaromatic ring systems can be substituted with C1 to C6 alkyl, C1 to C6 alkoxy, bromine, chlorine and fluorine;
c) are structure units with the following formulas (V) and (W) 
xe2x80x83wherein
Y and Z, independently of one another are O, S, CH, CH2 or NR8, the R8 group is selected from the group D comprising C1 to C6 alkyl, C1 to C6 acyl and hydrogen, and R5 in each case is a substituent from group A, n being defined as above; and R6 and R7, independently of one another, are hydrogen and/or a C1 to C6 alkyl group, with the proviso that, when Y in formula (V) is NR8, Z is a carbon atom;
or
d) B and Bxe2x80x2 form with one another an unsubstituted, monosubstituted or disubstituted fluorene-9-ylidene group or a saturated hydrocarbon group, which is C3 to C12, spiro-monocyclic, C7 to C12 spiro-bicyclic and/or C7-C12 spiro-tricyclic, the fluoreno substituents being selected from Group A.
Pursuant to the invention, compounds, the absorption wavelengths of which are hardly shifted from those of the framework, but which, at the same time, show in a surprising manner a significantly improved decolorization in comparison to compounds of the state of the art, are prepared by a simple ring formation at the f side of the naphthopyran framework. Compared to the pentahydrophenanthro[9,10-b]pyrans and tetrahydrocyclopenta[c]-naphtho[1,2-b]pyrans, which are described in the WO 99/20619 and differ from the inventive napthopyrans owing to the fact that an unsubstituted cyclopentane ring or an unsubstituted cyclohexane ring, in which X is xe2x80x94(CH2)2xe2x80x94 or xe2x80x94(CH2)3xe2x80x94 and R2 and R3 each are hydrogen, is linked at the f side of the naphthopyran framework, the inventive compounds exhibit a distinctly more rapid decolorization and significant improvements in the service life. Furthermore, yellowing no longer occurs in the case of the inventive compounds.
In a preferred embodiment, the carbon atoms in the X ring element are saturated, as a result of which corresponding cycloaliphatic ring systems, substituted with the R2 and R3 groups, are formed at the f side of the naphthopyran.
The carbon atoms in the X ring element may be unsubstituted, as well as monosubstituted or disubstituted. In the latter case, the substituents or substituents may be selected from group A consisting of C1 to C6 alkyl, C1 to C6 alkoxy, phenyl, bromine, chlorine and fluorine.
Pursuant to the present invention, photochromic 2H-naphtho[1,2-b]pyrans of formula (I) are also prepared, which structurally have spiro systems annellated at the f side of the naphthopyran system, the spiro system being formed by the ring system, formed by the ring element X at the f side of the naphthopyran, and the R2 and R3 group bound to the central spiro carbon atom. The R2 and R3 groups together with inclusion of the spiro carbon atoms, form a 5- to 11-membered ring and preferably a 5- to 7-membered ring, to which once again aromatic or heteroaromatic ring systems can be annellated. In other words, adjacent carbon atoms in the part of the spiro system, formed by R2 and R3, can belong to further ring systems, namely a ring system from the C group, consisting of benzene, naphthalene, phenanthrene, pyridine, quinoline, furan, thiophene, pyrrol, benzofuran, benzothiophene, indol and carbazol. Of course, these ring systems of group C can be unsubstituted as well as monosubstituted or disubstituted, the substituents being selected from the group A defined above.
Photochromic 2H-naphtho[1,2-b]pyrans, produced pursuant to the invention, have the following general formula (II), 
wherein n, R1, R2, R3 and X are defined as above with the proviso that the R1 groups and n in each case can be the same or different.
In a further embodiment, photochromic 2H-naphtho[1,2-b]pyrans are prepared, which have the following formula (III), 
wherein n, R1, X, B and Bxe2x80x2 are defined as above.
Especially preferred inventive compounds are:
1) spiro-9xe2x80x2-xanthene-5-[2-(4-methoxyphenyl)-2-phenyl-5,6,7,8-tetrahydro-6,6,7,7-tetramethyl-phenanthro[9,10-b]pyran]
2) spiro-9xe2x80x2-fluorene-5-{2-[4-(N-morpholinyl)phenyl]-2-phenyl-5,6,7,8-tetrahydrophenanthro[9,10-b]pyran}
3) 5-hydroxy-2,2,5-triphenyl-5,6,7,8-tetrahydro-phenanthro[9,10-b]pyran
4) spiro-9xe2x80x2-{(9,10-dihydroanthracene)-5-2,2-bis(4-methoxyphenyl)]cyclopenta[f]naphtho[1,2-b]pyran}
5) 2-[4-(N-morpholinyl)phenyl]-2-phenyl-5-oxo-cyclopenta[f]naphthopyran
6) 2-[4-(N-morpholinyl)phenyl]-2-phenyl-5,6,7, 8-tetrahydro-5-oxo-phenanthro[9,10-b]pyran]
7) spiro-9xe2x80x2-fluorene-5-[2-(4-methoxyphenyl)-2-phenyl-cyclopenta-[f]naphtho [1,2-b]pyran]
8) spiro-9xe2x80x2-xanthene-5-{-2-[4-(N-morpholinyl)phenyl]-2-phenyl-5,6,7,8-tetrahydro-6,6,7,7,-tetramethyl-phenanthro[9,10-b]pyran}
9) spiro-9xe2x80x2-fluorene-5-[2-(4-methoxyphenyl)-2-phenyl-cyclohepta[f]naphtho[1,2-b]pyran] and
10) spiro-9xe2x80x2-fluorene-5-[2-(4-methoxyphenyl)-2-phenyl-oxepano[3,2-f]naphtho[1,2-b]pyran].
The inventive, photochromic 2H-naphtho[1,2-b]pyrans with the general formula (I) can be synthesized employing principles, which are basically known in the field. In this connection, reference is made particularly to the synthesis methods described in WO 99/15518 and in the German patent application 199 02 771.4. For example, the inventive photochromic 2H-naphtho[1,2-b]pyrans can be synthesized according to the following general outline of the reactions, without being limited to these, n, X, R2, R2, R3, B and Bxe2x80x2 being defined as above. 
The keto group can be derivatized in the second step of the general reaction outline by generally known methods, such as the reaction with appropriate Grignard reagents.
The inventive compounds can be used in plastic materials or plastic objects of any type and shape for a plurality of purposes, for which the photochromic behavior is of importance. Moreover, a dye of the present invention or a mixture of such dyes can be used. For example, the photochromic naphthopyran dyes of the present invention can be used in lenses, particularly in ophthalmic lenses, lenses for eyeglass of all types, such as ski goggles, sunglasses, motorcycles goggles, visors of helmets and the like. Moreover, the inventive naphthopyrans can also be used, for example, as sun protection in vehicles and residences in the form of windows, protective shutters, coverings, roofs or the like.
To prepare such photochromic objects, the inventive photochromic naphthopyran dyes can be applied by various methods, described in the state of the art, such as those already given in WO 99/15518, on a polymer material, such as an organic synthetic resin material, or embedded therein.
In this connection, a differentiation is made between bulk dyeing methods and surface dyeing methods. A bulk dye method comprises, for example, the dissolving or dispersing of the inventive photochromic compound or compounds in a synthetic resin material, for example, by the addition of the photochromic compound or compounds to a monomeric material, before polymerization takes place. A further possibility of producing a photochromic object is the penetration of the synthetic resin material or materials with the photochromic compound or compounds by immersing the synthetic resin material in a hot solution of the photochromic dye or dyes of the present invention or, for example, by a heat transfer method. The photochromic compound or compounds can also be provided, for example, in the form of a separate layer between adjoining layers of the synthetic resin material, such as a part of a polymeric film. Moreover, the photochromic compound or compounds can also be applied as part of a coating present on the surface of the synthetic resin material. The expression xe2x80x9cipenetrationxe2x80x9d is intended to signify the migration of the photochromic compound or compounds into the synthetic resin material, for example, by the solvent-supported transfer of the photochromic compound or compounds into a polymer matrix, by the vapor face transfer or by different types of surface diffusion processes. Advantageously, such photochromic objects, such as eyeglass lenses, can be produced not only by means of the conventional bulk dyeing, but also, in a similar manner, by means of surface dyeing. For the latter variation, a surprising slight tendency to migrate can be achieved. This is of advantage especially for the subsequent finishing steps, since layer detachments and similar defects are drastically reduced, for example, during an anti-reflection coating, due to the lesser back diffusion under vacuum.
Overall, on the basis of the inventive photochromic 2H-naphtho[1,2-b]pyrans, any dyes, which are compatible from a chemical and color point of view, can be applied on or embedded in the synthetic resin material in order to satisfy esthetic points of view as well as medical or fashion points of view. The dye or dyes, specifically selected, can therefore be varied depending on the intended effect as well as on the requirements.